Thousands of troops from NATO and its partner nations are training on land and sea in central and eastern Europe.
Though he denied the Russian state had been involved in hacking, Putin said individual "patriotic" hackers could mount their own attacks.
Russian state gas exporter Gazprom, which supplies around a third of the EU's gas, is keen for Nord Stream 2 to be built by 2019.
Team USA put an end to Russia’s winning streak at the 2017 IIHF World Championship edging the ‘Red Machine’ 5-3 in the final minutes.
The final result was decided by a 50/50 combination of jury and public votes.